The present invention relates to a conveying apparatus for holding and conveying containers or bottle blanks, and more particularly to a conveying apparatus including an elongated chain or endless chain composed of multiple chain elements serially connected with each other. A clamping pawl is disposed on each chain element for tightly leaning against the inner wall of the opening of the container so as to hold the container and make the container move in a predetermined direction.
U.S. Pat. No. 5,857,562 discloses a conveying device for conveying preforms. The conveying device includes one single chain capable of holding and conveying the preforms. The chain is composed of multiple plates each having a section on which a holding member is disposed and a section for serially connecting an adjacent plate.
Each mounting plate is formed with a vertical hole and a transverse hole perpendicular to each other. The body of a holding structure is fitted in the vertical hole, while a linking stem of another plate is fitted in the transverse hole. The linking stem extends onto an inner end of the plate and is equipped with a spherical seat portion and a nut, whereby multiple plates together form an endless chain for conveying preforms.
The above chain composed of the plates has some shortcomings as follows:
1. The linking stem must have a longer length to form a certain gap between the outer periphery of two adjacent plates so as not to interfere with the relative swinging of the plates. However, under such circumstance, the elongated linking stem will slide left and right within the transverse-hole so that great noise will be produced in use of the chain due to loosening thereof.
2. The vertical hole and the transverse hole communicate with each other. Therefore, in the above state, once the linking stem moves toward the vertical hole, the nut at the end of the linking stem will abut against the periphery of the body of the holding structure in the vertical hole. This will hinder the movement of the holding structure.
3. The chain is driven only in one specific direction. Such limitation of direction leads to inconvenience in assembly and operation.
4. The spherical seat and the body of the holding structure are together installed in the interior space of the main body. Therefore, when a user wants to replace a worn out spherical seat, it is necessary to totally detach the holding structure for the replacement. Such procedure is quite troublesome.
In addition, the respective holding structures mounted on the plates are used to hold those containers with an opening. The holding structure especially clamps and holds the container at the opening thereof for conveying the container. U.S. Pat. No. 4,846,656 discloses a structure for holding the container. The structure is a shaft rod which can be directly passed through and plugged into the opening of the container. By means of the high frictional coefficient of the surface of the shaft rod, the shaft rod can be fixedly engaged with the inner wall of the opening of the container. Therefore, the container can be drawn and moved along with the shaft rod and a conveying device on which the shaft rod is retained.
When the container is moved along with the shaft rod to pass through a heating device, the shape of the opening of the container will not be over-deformed. However, there are still some shortcomings existing in such structure. First, the structure lacks a withdrawing structure. Therefore, after the held container is processed and moved to another position, it is difficult to release the container from the end of the shaft rod. Second, the shaft rod has fixed outer diameter so that in the case the inner diameter of the opening of the container is slightly different, the shaft rod may be too tightly fitted in the opening and can be hardly detached therefrom or the shaft rod may be too loose to hold the container.
It is therefore a primary object of the present invention to provide a container conveying apparatus which is movable without limitation of direction and can be pulled or pushed left and right.
It is a further object of the present invention to provide the above container conveying apparatus by which the noise produced in operation is greatly lower than the conventional apparatus.
It is still a further object of the present invention to provide the above container conveying apparatus in which the bearing can be very easily replaced.
It is still a further object of the present invention to provide the above container conveying apparatus which is able to easily hold and release a container.
It is still a further object of the present invention to provide the above container conveying apparatus which is able to firmly hold different containers with different inner diameters of the openings.
It is still a further object of the present invention to provide the above container conveying apparatus in which a Predetermined section is outward expanded to tightly lean against the inner wall of the opening of the container so as to more reliably hold the container.
The present invention can be best understood through the following description and accompanying drawings wherein: